Passenger vehicles often include electric batteries for operating features of a vehicle's electrical and drivetrain systems. For example, vehicles commonly include a 12V lead-acid automotive battery configured to supply electric energy to vehicle starter systems (e.g., a starter motor), lighting systems, and/or ignition systems. In electric, fuel cell (“FC”), and/or hybrid vehicles, a high voltage (“HV”) battery system (e.g., a 360V HV battery system) may be used to power electric drivetrain components of the vehicle (e.g., electric drive motors and the like). For example, an HV rechargeable energy storage system (“ESS”) included in a vehicle may be used to power electric drivetrain components of the vehicle.
The electrical behavior of a battery system may change over time as the battery system ages. For example, a charge capacity of the battery system may decrease over time and an equilibrium voltage (e.g., an open circuit voltage (“OCV”) of the battery system for a given state of charge (“SOC”) may shift from its value at the beginning-of-life (“BOL”) of the battery system. Conventional methods used in connection with estimating battery system parameter and/or performance information, including battery capacity information, may not account for such changes and may assume that an OCV/SOC relationship for the battery system is static throughout its life. Accordingly, such methods may result in progressively less accurate estimations over time.